Does the podcast video playback speed affect comprehension for novel curriculum delivery? A randomized trial

Introduction: Medical education is a rapidly evolving field that has been using new technology to improve how medical students learn. One of the recent implementations in medical education is the recording of lectures for the purpose of playback at various speeds. Though previous studies done via surveys have shown a subjective increase in the rate of knowledge acquisition when learning from sped-up lectures, no quantitative studies have measured information retention. The purpose of this study was to compare mean test scores on written assessments to objectively determine if watching a video of a recorded lecture at 1.5x speed was significantly different than 1.0x speed for the immediate retention of novel material. Methods: Fifty-four University of Kentucky medical students volunteered to participate in this study. The subjects were divided into two separate groups: Group A and Group B. Each group watched two separate videos, the first at 1.5x speed and the second at 1.0x speed, then completed assessments following each. The topics of the two videos were ultrasonography artifacts and transducers. Group A watched the artifacts video first at 1.5x speed followed by the transducers video at 1.0x speed. Group B watched the transducers video first at 1.5x speed followed by the artifacts video at 1.0x speed. The percentage correct on the written assessment were calculated for each subject at each video speed. The mean and standard deviation were also calculated using a t-test to determine if there was a significant difference in assessment scores between 1.5x and 1.0x speeds. Results: There was a significant (p=0.0188) detriment in performance on the artifacts quiz at 1.5x speed (mean 61.4; 95% confidence interval [CI]-53.9, 68.9) compared to the control group at normal speed (mean 72.7; 95% CI- 66.8, 78.6). On the transducers assessment, there was not a significant (p=0.1365) difference in performance in the 1.5x speed group (mean 66.9; CI-59.8, 74.0) compared to the control group (mean 73.8; CI- 67.7, 79.8). Conclusion: These findings suggest that, unlike previously published studies that showed subjective improvement in performance with sped-up video-recorded lectures compared to normal speed, objective performance may be worse.